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  • 1985-1989
  • 1975-1979  (836)
  • 1890-1899
  • 1976  (836)
  • Organic Chemistry  (693)
  • Engineering General  (143)
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Years
  • 1985-1989
  • 1975-1979  (836)
  • 1890-1899
Year
  • 101
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1183-1187 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 4 Ill.
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  • 102
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 103
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1233-1247 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Employing experiments, Correlation Analysis, the method of ‘least square estimation’, and a special computational program, the problem of similarity between the variables of the soil-machine system during soil compaction is examined. The solution, based on the probability theory of ‘Analysis of Variance’, consists in developing the stochastic model which defines the variables and their interactions for different systems.In this particular case of soil compaction by cylinders the theorem of Vaschy-Buckingham or Pi terms is used to define the mononyms (terms) of similarity.The stochastic model, operant in every case, consists of an ellipsoid characteristic of the particular cylinder and its variables, so that greatest soil compaction at a given depth is achievable with a probability of 95 per cent at a level of significance of α = 0.05.
    Additional Material: 4 Ill.
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  • 104
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1289-1298 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Let F be a continuous real-valued function defined on [-1, 1] × [-1,1]. For purposes of simplifaction in some numerical processes, one may desire to have an approximation of the function F. We present a known method of approximation called the best rational product approximation. When developing this approximation to F, certain types of discontinuities may arise. We develop a slight variation of a known technique to overcome such discontinuities. With this modified technique, it is then possible to develop a computer program to compute the approximation of F. A brief discussion of this program is presented along with some of the results which we have obtained.
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  • 105
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1357-1367 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In this paper, we have derived some new higher order difference formulas for the solution of a fourth order parabolic partial differential equation governing transverse vibrations of a uniform flexible beam in one and two space dimensions using Richtmyer's approach and a direct approach. Two examples illustrate the utility of the new difference methods.
    Additional Material: 2 Ill.
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  • 106
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1397-1403 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 3 Ill.
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  • 107
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 1407-1410 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The estimation of the parameters (‘fictitious densities’) which control the convergence and numerical stability of a non-linear Dynamic Relaxation solution is described. The optimal values of these parameters vary during the iterative solution and they are predicted from the Gerschgörin bounds, that is rowsums of the stiffness matrix, which are divided into constant and variable parts for computational convenience. The procedure is illustrated by reference to the analysis of an axially loaded beam on a non-uniform elastic foundation.
    Additional Material: 1 Ill.
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  • 108
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
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  • 109
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 39-58 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element formulation is presented to study the non-linear buckling of arbitrary shallow elastic thin shells with general boundary conditions and subjected to conservative pressure loading. Pre and post buckling behaviour of a large number of shallow and semi deep doubly curved shells is studied in detail. Unsymmetrical bifurcation paths of a shallow spherical shell subjected to uniform inward pressure are also investigated.
    Additional Material: 7 Ill.
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  • 110
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 115-122 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents theory and examples of partial approximation as a modification of the displacement method in the finite element analysis. This method requires different shape functions for different terms in the potential energy expression to curtail the processes in the standard displacement method. Explanation of the theory is given by use of a simple example for Poisson's equation. It can also be effectively utilized to give mathematical foundation to some finite element models based on physical reasonings, such as Melosh's rectangular element for plate bending and beam element approximation of circular arches.
    Additional Material: 4 Ill.
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  • 111
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 133-143 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the present paper it is shown how to achieve special interpolation functions that can be applied to the finite element method, least squares methods or other related numerical techniques. We call these functions sequential interpolation functions since one of the main characteristics of this technique refers to the fact that the refinement of the solution does not require the redefinition of the interpolation funtions used in a previous step, as the case for instance in the FEM.The present theory and the FEM using an isoparametric element were compared for a plane stress problem. The results show that both have the same degree of accuracy. The choice of the sequential interpolation functions is easier than those used in the finite element formulation and the computer time was reduced by about 50 per cent.
    Additional Material: 5 Ill.
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  • 112
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 211-223 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Independent variable transformations of partial differential equations are examined with regard to their use in numerical solutions. Systems of first order and second order partial differential equations in conservative and nonconservative form are considered. These general equations are transformed using generalized mapping functions and important computational features of the transformed equations are discussed. Examples of mappings which regularize domains are given involving various types of partial differential equations. These mappings are of particular importance in finite difference approximations because of the ease with which a mesh can be adapted to regions formed by co-ordinate lines.
    Additional Material: 5 Ill.
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  • 113
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 238-240 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 114
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 263-281 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Early attempts to construct a triangular finite element for plate bending problems from a compatible cubic displacement field are not entirely satisfactory. The present paper shows how an accurate plate element can be achieved using independent cubic polynomial assumptions for the internal and boundary displacements in conjunction with a modified potential energy principle. This approach yields a simple algebraic formulation with favourable connection quantities at the element vertices which will appeal to practical users of the conventional finite element displacement method. Moreover, in Appendix I it is shown that the cubic element is identical to a previous hybrid stress element with linear internal bending and twisting moments and cubic boundary displacements. The stresses obtained from the former hybrid finite element solution therefore satisfy the strain compatibility conditions exactly. This remarkable result has an important significance in the theory of hybrid finite elements.
    Additional Material: 2 Ill.
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  • 115
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 535-549 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A method to produce efficient piecewise uniform stiffened shells of revolution is presented. The approach uses a first order differential equation formulation for the shell prebuckling and buckling analyses and the necessary conditions for an optimum design are derived by a variational approach. A variety of local yielding and buckling constraints and the general buckling constraint are included in the design process. The local constraints are treated by means of an interior penalty function and the general buckling load is treated by means of an exterior penalty function. This allows the general buckling constraint to be included in the design process only when it is violated. The self adjoint nature of the prebuckling and buckling formulations is used to reduce the computational effort. Results for four conical shells and one spherical shell are given.
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  • 116
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 565-577 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In applications of the finite element method to complicated nonlinear problems, it is proposed to simplify the operator in each element, typically by a linerization process. Local approximations can then be more easily constructed in the usual manner, and a proper assembly can be made. Such an approach would lead to an approximate global variational statement; or if the variational principle exists but is hard to handle, it should suggest an iterative scheme with a built-in physical basis, hence a better chance to converge. The case of high subsonic flow over a circular cylinder is studied in detail by this method. With linear triangular elements, numerical results are obtained for 100 nodal unknowns in each quadrant. The convergence is extremely rapid up to a free stream Mach number of 0.42, slightly above critical. The accuracy is excellent as compared against Imai's analytical results.
    Additional Material: 3 Ill.
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  • 117
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 647-663 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A FORTRAN IV algorithm is presented for determining sets of dominant eigenvalues and corresponding eigenvectors of symmetric matrices. It is also extended to the solution of the equations of natural vibration of a structure for which symmetric stiffness and mass matrices are available. The matrices are stored and processed in variable bandwidth form, thus enabling advantage to be gained from sparseness in the equations. Some of the procedures may also be used to solve symmetric positive definite equations such as those arising from the static analysis of structures loaded within the elastic range.
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  • 118
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 703-708 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Two quadrature rules based on nodes in a rhombus are used to evaluate integrals over a square with integrands which are singular on a diagonal. The rules are also compared for non-singular integrals with an equivalent product Gauss rule.
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  • 119
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 719-720 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 120
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 747-766 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The purpose of this paper is to present refinements in a steepest descent algorithm for optimal design of structures and numerical experience that demonstrates its numerical efficiency. The algorithm is based on a state space optimization technique that was initially developed and applied to optimal control problems. Design constraints are divided into four distinct subsets, the special characteristics of which are exploited to improve computational efficiency of the algorithm. Some further improvements in structural analysis, design sensitivity analysis, and constrained steepest descent programming calculations are presented. Optimum designs for three test problems are obtained and convergence rates are compared with results presented in the literature.
    Additional Material: 4 Ill.
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  • 121
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 767-785 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The coupled thermomechanical behaviour of a layer of thermorheologically simple material bonded to a uniformly rotating rigid cylinder and indented by another rigid cylinder is studied by the finite element method. The various approximations necessary to reduce the problem to one of tractable size and the computational methods used are discussed in some detail. The complete thermal, deformation and stress fields may be computed. Some results, computed for a grid using ‘rectangular’ elements, presented graphically include the temperature distribution, the stress distribution near the bond surface, the contact pressure distribution and the asymmetric surface deformation of the rubberlike layer.
    Additional Material: 8 Ill.
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  • 122
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 809-825 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents the formulations of essentially one-dimensional least squares and Galerkin-least squares finite elements for the numerical solution of two-dimensional laminar boundary layer equations. An iterative technique to cope with the non-linearity of the boundary layer equations, in conjunction with the least squares finite element method, is proposed. Through exhaustive numerical investigations in the retarded flow over a plate, flow past a circular cylinder, the flow past an elliptic cylinder, the accuracy and applicability of the proposed method are demonstrated.
    Additional Material: 8 Ill.
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  • 123
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 861-872 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element for the analysis of rotational shells using a mixed variational formulation is proposed. The element has arbitrary curvature in the meridional plane, its geometry being given by the values of the axial and radial co-ordinates, slope and meridional curvature at the nodal circles. A linear variation in the thickness was included in the formulation as was an orthotropic material. Test cases of flat plates and spherical shells indicate that a high degree of accuracy is obtainable with relatively small number of elements.
    Additional Material: 5 Ill.
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  • 124
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 893-923 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The integral equations which arise from application of the Galerkin-finite element scheme to the convective diffusion equation are examined to illustrate how this method represents differential equations. The formulae obtained are effectively spatial averages of standard finite difference equations written at a node. The truncation error in the finite element solution at a node is obtained for various nodal configurations.
    Additional Material: 9 Tab.
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  • 125
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 10 (1976), S. 945-949 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element may satisfy all convergence requirements and work well except for being too stiff or too flexible when the mesh is coarse. Here we discuss a technique for softening or stiffening such elements, provided that they have internal degrees-of-freedom. The technique is applied to a previously derived plate element, and the element is found to be much improved.
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  • 126
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 974-974 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 127
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 976-976 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 128
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 991-1005 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The field equations of three-dimensional elastostatics are transformed to boundary integral equations. The elastic body is divided into subregions, and the surface and interfaces are represented by quadrilateral and triangular elements with quadratic variation of geometry and linear, quadratic or cubic variation of displacement and traction with respect to intrinsic co-ordinates. The integral equation is discretized for each subregion, and a system of banded form obtained. For the integration of kernel-shape function products, Gaussian quadrature formulae are chosen according to upper bounds for error in terms of derivatives of the integrands. Use of the integral formulation is illustrated by the analysis of a prestressed concrete nuclear reactor pressure vessel.
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  • 129
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1057-1064 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The unique capability of calculating single points by Monte Carlo Methods is used in an attempt to develop an efficient Monte Carlo method for whole field calculations of heat conduction problems. Rather than calculate the whole field by Monte Carlo, only select points around the boundaries of inscribed figures of standard shapes are are so calculated. Interior points of the inscribed figures are then calculated by analytical (non-numerical) techniques. The procedure is described and shown to be more efficient than previously published Monte Carlo modifications but not as efficient as the Gauss-Seidel method. This new procedure will most likely be competitive for subregion calculations rather than for whole field calculations (for which standard numerical procedures are most efficient) or for single point calculations (for which other Monte Carlo methods are most efficient).
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  • 130
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1143-1152 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Finite element techniques are developed for the analysis of high-speed three-dimensional free surface flows within the context of potential flow theory. The primary dependent variable is the velocity potential, which is approximated as a quadratic within each isoparametric element. An iterative approach is used to seek the initially unknown free surface location.A high-speed fluid jet issuing through an orifice plate into a transvese gravity field is examined to illustrate features of the approach. Convergence of the solutions is very good at a Froude number of 3-53 but deteriorates as F nears unity.
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  • 131
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1179-1182 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 4 Ill.
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  • 132
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1191-1193 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 133
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 853-860 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper describes numerical techniques which have been developed in order to solve the load flow problem of a power system network probabilistically instead of using normal deterministic methods. The aim in the development of these techniques has been to reduce the computational time and storage commensurate with maintaining a high degree of accuracy.
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  • 134
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 925-933 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 135
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 950-953 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Large scale non-linear programming problems with non-linear constraints are of practical concern in the areas of process control and system design. Although advances in computer technology address these problems, more efficient algorithms are needed. An algorithm currently used is Rosen's Gradient Projection Method. This note presents an alternative technique of performing the steps for finding the projected gradient used in Rosen's method, a technique that gives equivalent results with fewer computations.
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  • 136
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 960-964 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Implicit difference methods for the wave equation in two space variables have been discussed with the help of a stability diagram. The difference methods of intermediate accuracy 0(h4+k2) have been determined. A method of order of accuracy 0(h2+k2) with minimum truncation error has also been found.
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  • 137
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 975-975 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 138
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 979-990 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An interative method to fit the function \documentclass{article}\pagestyle{empty}\begin{document}$\mathop \[y = \sum\nolimits_i^n { = 1} a_i e^{lix}\] $\end{document} to data is considered. The technique used is that of inversion of a linear differential operator with constant coefficients. This method reproduces the parameters for mathematically precise data and gives satisfactory results when the data are affected by random errors.
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  • 139
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1077-1095 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element Galerkin formulation admitting non-homogenous boundary conditions and discontinuous approximants is derived from a variational principle. The procedure results in matrix equations explicitly allowing for jump discontinuties across interelement boundaries. As an illustration, a specialization of the procedure similar to a reduced integration technique is used to solve several problems in elastostatics. The improvement in accuracy in comparison with conventional methods is remarkable.
    Additional Material: 14 Ill.
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  • 140
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1097-1114 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents an optimization method based on optimality criterion for minimum weight of structures with stability requirements. A recurrence relation is derived and the method is explained in the context of the displacement method of finite element analysis. The incipient buckling of the structure is determined by a linear eigenvalue solution. The method is programmed for trusses and frames. Illustrative problems are given to show the applicability of the method of design of structures with a large number of design variables.
    Additional Material: 5 Ill.
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  • 141
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1177-1178 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 142
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1427-1428 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 143
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    International Journal for Numerical Methods in Engineering 10 (1976), S. 1420-1426 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 2 Ill.
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  • 144
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 343-346 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 145
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 321-326 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solvent-induced Changes of the Electronic Structure of Negatively Solvatochromic DyesThe 1H NMR chemical shifts of negatively solvatochromic dyes depend on the polarity of the solvent used. The differences of the chemical shifts of vicinal protons decrease with increasing polarity. This result supports the idea that the electronic structure of negatively solvatochromic dyes changes from a polymethine-like state in non-polar solvents to a polyene-like state in polar solvents.
    Notes: Die chemischen Verschiebungen des Protonenresonanzspektrums von negativ solvatochromen Farbstoffen hängen von der Polarität des verwendeten Lösungsmittels ab, wobei die Differenzen der chemischen Verschiebungen benachbarter Protonen mit zunehmender Polarität abnehmen. Dies deutet auf eine lösungsmittelinduzierte Veränderung der Elektronenstruktur von einem mehr polymethinähnlichen Zustand in unpolaren Lösungsmitteln in Richtung auf einen polyenähnlichen Zustand in polaren Lösungsmitteln hin.
    Additional Material: 3 Ill.
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  • 146
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 381-389 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Phenyl-substituted Alkene-diynes by Alkaline Degradation of Quaternary Salts of Mannich Bases Derived from Phenyl-alka-1,3-diynesIsomeric phenyl- and p-methoxyphenylsubstituted hexenediynes are formed by alkaline degradation of quaternary salts of aryldiacetylene-Mannich bases. The reaction is a diethynylogic Hofmann elimination. The degradation with sodium amide mainly results in the formation of trans-alkenediynes with a terminal triple bond. Using aqueous potassium hydroxide, the degradation yields the isomers with terminal double bond exclusively. This is in contrast to the reaction of aliphatic diacetylene-Mannich base methoiodides.
    Notes: Isomere Phenyl- und p-Methoxyphenylhexendiine werden durch alkalischen Abbau quartärer Salze von Aryldiacetylen-Mannichbasen über eine diäthinyloge Eliminierung erhalten. Der Abbau mit Natriumamid ergibt bevorzugt die Alkendiine mit endständiger Dreifachbindung in der trans-Konfiguration. Beim Abbau mit wäßriger Kalilauge entstehen im Gegensatz zu den nicht phenylsubstituierten Diacetylen-Mannichbasen ausschließlich die Isomeren mit endständiger Doppelbindung.
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  • 147
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 483-488 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Steroids. XLVIII. 16 α-Heterosubstituted 3-Methoxy-estra-1,3,5(10)-triene-17β-olsThe synthesis of 16α-heterosubstituted 3-methoxy-estra-1,3,5(10)-triene-17β-ols 2a - 2e from 16β-bromo-3-methoxy-estra-1,3,5(10)-triene-17β-ol 1 by substitution with nucleophiles is described. Additional compounds of this class 2f - 2h are obtained by transformation of the new 16α-substituents. Jones oxidation of 2b and 2c yields the 17-keto compounds 3b and 3c. The configuration of the new compounds is confirmed by i.r. and 1H n.m.r. spectra.
    Notes: Die Darstellung von 16α-heterosubstituierten 3-Methoxy-östra-1,3,5(10)-trien-17β-olen 2a - 2e aus 16α-Brom-3-methoxy-östra-1,3,5(10)-trien-17β-ol 1 durch Substitution mit Nucleophilen wird beschrieben. Durch Umwandlung der eingeführten 16β-Substituenten sind weitere Vertreter dieser Verbindungsklasse 2f - 2h zugänglich. Die Verbindungen 2b und 2c werden durch Jones-Oxidation in die 17-Keto-Verbindungen 3b und 3c überführt. Die Konfiguration der Verbindungen wird durch IR- und 1H-NMR-Spektroskopie gesichert.
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  • 148
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 816-822 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Stobbe-Kondensation mit substituierten Bernsteinsäureestern. III. Synthese von Benzofuran- und Indol-DerivatenDie Kondensation von 1-Methylpyrrolyl-2-carbaldehyd mit Methyl-bernsteinsäure-dimethylester in Gegenwart von Natriumhydrid ergab überwiegend den entsprechenden E-Halbester 1a. Im Gegensatz dazu führte die Kondensation von 1-Methylpyrrolyl- bzw. Furyl-2-carbaldehyd mit Phenylbernsteinsäure-dimethylester unter Verwendung von Kalium-tert.-butylat oder Natriumhydrid zu einem Stereoisomerengemisch der E- und Z-Halbester. Die Cyclisierung der E-Halbester ergab die entsprechenden Benzofuran- und Indol-Derivate 2, während durch Hydrolyse die E-Dicarbonsäuren 6 entstanden, die zu den entsprechenden Anhydriden umgesetzt wurden.
    Notes: The condensation of 1-methyl-pyrrolyl-2-carboxaldehyde with dimethyl methyl-succinate in presence of sodium hydride gave predominantly the corresponding E-half ester 1a. However, the condensation of either 1-methyl-pyrrolyl- or furan-2-carboxaldehyde with dimethyl phenylsuccinate using either the potassium t-butoxide or sodium hydride method produced a stereoisomeric mixture of E- and Z-half -esters. Cyclisation of the E-half-esters gave the corresponding benzofuran and indole derivatives 2; whereas their hydrolysis produced the E-dibasic acids 6, which were converted to the corresponding anhydrides 7.
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  • 149
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 801-815 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: MO-LCAO Calculations on Polymethines. IV Contribution towards DÄHNE'S Conception of Coupled PolymethinesStarting from a quantumchemical characterization of the polymethine π-electron system covered in the previous papers the significance of streptopolymethine sub-structures in more complicated molecular entities has been investigated. In order to relate the electronic structure of a composite system to those of its constituent parts the electronic wave functions are subjected to the configuration analysis. Indices have been employed to evaluate the localizability of the atomic or molecular sub-systems. According to these indices many structures may be considered as being composed from polymethinic, polyenic and aromatic fragments. In the case of the several carbo-and heterocyclic π-systems serious shortcomings of the composite system approach are clearly indicated. Scope and limitation of this model can, however, easily be recognized by application of the simple second order perturbation theory.
    Notes: Ausgehend von einer quantenchemischen Charakterisierung des Polymethinzustandes, die in den vorangegangenen Arbeiten behandelt wurde, wird die Bedeutung der Streptopolymethin-Teilsysteme für komplizierte molekulare Strukturen untersucht. Um die Elektronenstruktur des zusammengesetzten Systems mit denen der partizipierenden Teilsysteme zu vergleichen, werden die elektronischen Wellenfunktionen der Konfigurationsanalyse unterworfen. Die Lokalisierbarkeit in atomare und molekulare Subsysteme wird durch Indizes bewertet. Danach können zahlreiche Strukturen aus polymethinischen, polyenischen und aromatischen Fragmenten zusammengesetzt gedacht werden. Bei einigen carbo- und heterocyclischen π-Systemen ist das Baukastensystem nur begrenzt anwendbar. Die Anwendungsbreite des Modells kann aber durch Anwendung der einfachen Störungstheorie 2. Ordnung leicht erkannt werden.
    Additional Material: 5 Ill.
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  • 150
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 823-834 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sydnone Ethylenes. I Stereoselective Synthesis of Sydnone Ethylenes from Sydnone AldehydesSydnones are formylated in 4-position by the VILSMEIER-HAAK reaction. N(3)-Methyl- and N(3)-(p-Anisyl)-sydnone-(4)-carboxaldehyde react stereoselectively to sydnone ethylenes with diethyl ethoxycarbonylmethanephosphonate by HORNER reaction and with arylmethylphosphonium salts by WITTIG reaction in the presence of strong bases. In the latter case, especially in the absence of lithium cations, Z-selectivity is observed which is explained by electronic interaction between the sydnone cyclus and the aromatic substituent of the phosphine ylid in the first step of the reaction. The configuration of the obtained Z- and E-sydnone ethylenes is determined by means of 1H-NMR- and IR-spectra.
    Notes: Sydnone lassen sich in 4-Position nach VILSMEIER-HAAK formylieren. N(3)-Methyl- und N(3)-(p-Anisyl)-sydnon-(4)-carbaldehyd werden mit Äthoxycarbonylmethan-phosphonsäurediäthylester nach HORNER und mit verschiedenen Arylmethylphosphoniumsalzen nach WITTIG in Gegenwart starker Basen stereoselektiv olefiniert. Im letzteren Fall tritt besonders in Abwesenheit von Lithiumkationen eine Z-Selektivität auf, die auf eine elektronische Wechselwirkung zwischen dem Sydnonring und dem aromatischen Substituenten des Phosphin-ylids im ersten Reaktionsschritt zurückgeführt wird. Die Konfigurationsbestimmung der resultierenden Z- und E-Sydnonäthylene erfolgt an Hand der 1H-NMR- und IR-Spektren.
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  • 151
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 835-842 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Pyrazolo[3,2-c]benzo-1,2,4-triazines and Pyrazolo [3,2-c]pyrido[4,3-e] [1,2,4]triazinesα,β-Unsaturated β-aminonitriles 1 condensate with 2-nitrophenylhydrazine and with 4-hydrazino-3-nitropyridine to yield the corresponding nitriles of β-keto acids 2 and 3, respectively. Bases achieve cyclisation of these compounds to pyrazolo[3,2-c]benzo-1,2,4-triazine-5-oxides 7 and pyrazolo[3,2-c]pyrido[4,3-e] [1,2,4]triazine-5-oxides 8, respectively. The N-oxides are reduced by means of sodium dithionite to the corresponding triazines 9, 10.
    Notes: α,β-Ungesättigte β-Aminonitrile 1 kondensieren mit 2-Nitrophenylhydra-zin und mit 4-Hydrazino-3-nitropyridin zu Hydrazonen von β-Ketosäurenitrilen 2 bzw. 3. Diese Verbindungen cyclisieren bei der Einwirkung von Basen zu Pyrazolo[3,2-c]benzo-1,2,4-triazin-5-oxiden 7 bzw. Pyrazolo[3,2-c]pyrido[4,3-e] [1,2,4]triazin-5-oxiden 8. Die N-Oxide lassen sich mittels Natriumdithionit zu den entsprechenden Triazinen 9, 10 reduzieren.
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  • 152
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 895-901 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Synthesis of Octahydroquinazolinones and their Reaction with PeracidBy reaction of cyclohexanone-2-carboxamide with ammonia and aldehydes, octahydroquinazolinones 2a-f, and with Schiff bases octahydroquinazolinones 3a-c are formed. 2-Hydroxycyclohexanone-2-carboxamide forms with ammonia and butyraldehyde the hydroxyocta-hydroquinazolinone 4. Compound 2e reacts with monoperoxiphthalic acid to the hydroxyoxaziridine 5e which reacts with alkali hydroxide to compound 6. 8 yields with peroxy acid the hydroperoxy epoxide 9.
    Notes: Bei Umsetzung von Cyclohexanon-2-carbonsäureamid mit Ammoniak und Aldehyden werden die Octahydrochinazolinone 2a-f, mit Schiffschen Basen die Octahydrochinazolinone 3a-c gebildet. 2-Hydroxycyclohexanoncarbonsäureamid bildet mit Ammoniak und Butyraldehyd das Hydroxyoctahydrochinazolinon 4. Verbindung 2e reagiert mit Monoperoxyphthalsäure zum Hydroxyoxaziridin 5e, das durch Natronlauge zu Verbindung 6 umgelagert wird. Aus 8 wird mit Persäure das Hydroperoxyoxaziridin 9 erhalten.
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  • 153
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 993-1007 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: CNDO/2 and VESCF-LCAO-MO Calculations of the Simplest Cyanines, Merocyanines, and OxonolesThe wave-functions and eigen-values of the simplest cyanines, merocyanines and oxonoles are calculated by means of the CNDO/2 method. From the charge distribution of the Σ-electrons obtained in this way the parameters of calculations by means of the VESCF-LCAO-MO method are determined. Thus one gets VESCF wave-functions which are free from special parametrisations. The calculated molecular parameters correlate well with experimental data, i.g. dipole moments, transition energies, transition probabilities, and n.m.r. parameters.
    Notes: Die Wellenfunktionen und Eigenwerte der einfachsten Cyanine, Merocyanine und Oxonole werden nach der CNDO/2-Methode berechnet. Aus der erhaltenen Ladungs-verteilung der Σ-Elektronen werden die Parameter für VESCF-LCAO-MO-Berechnungen bestimmt. Auf diese Weise erhält man im Rahmen der π-Elektronennäherung VESCF-Molekülwellenfunktionen, die von speziellen Parametrisierungen frei sind und in befriedigender Weise mit experimentellen Parametern, wie Dipolmomenten, Übergangsenergien, Übergangswahrscheinlichkeiten und NMR-Parametern korrelieren.
    Additional Material: 5 Ill.
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  • 154
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1008-1018 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Action of Strong Bases on Quaternary Methallylammonium Compounds. III. Base-initiated Rearrangement of Methyldialkyl- and Trialkylmethallylammonium SaltsMethyl-diethyl-, methyl-dipropyl- and methyl-dibutyl-methallylammoniumiodide rearrange in the presence of sodium amide, sodium methylsulfinylcarbanion or butyllithium to give mainly the products of the [1,2]-Stevens-rearrangement with methallyl-ylid as an intermediate. Products of [1,2]-rearrangement of the bulky alkyl-groups with alkyl-ylid as an intermediate are formed in small amounts.In contrast to this and to the known degradation of trimethyl- and dimethylalkyl-methyallyl-ammonium salts the action of the bases on triethyl-, tripropyl- and tributyl-methallylammonium salts gives also the [1,4]-besides the [1,2]-rearrangement.
    Notes: Methyl-diäthyl-, Methyl-dipropyl- und Methyl-dibutyl-methallyl-ammoniumjodid liefern bei der Einwirkung von Natriumamid, Methylsulfinyl-carbanion oder Butyllithium bevorzugt [1,2]-Stevens-Umlagerungsprodukt über das Methallyl-Ylid. [1,2]-Verschiebungen der größeren Alkylgruppen über Alkyl-Ylide konnten nur in geringem Maße festgestellt werden.Im Gegensatz dazu und zu den schon früher beschriebenen Abbaureaktionen von Trimethyl- und Dimethylalkyl-methallyl-ammoniumsalzen wurden durch die Baseneinwirkung auf Triäthyl-, Tripropyl- und Tributyl-methallyl-ammoniumhalogenide zusätzlich zu den [1,2]- in größerem Umfang auch [1,4]-Umlagerungen nachgewiesen.
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  • 155
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Sulphochlorination of Paraffins. I. Kinetic Studies on the Monosulphochlorination of the n-Paraffins C6—C16The monosulphochlorides in the reaction mixtures of the sulphochlorination of n-paraffins may be transformed into the gaschromatographic separable sulphonic acid dimethyl amides by reaction with dimethylamine in ether.So the analysis of the isomers in the mixtures from sulphochlorination of n-paraffins C5—C16 becomes possible. The results together with the relative rates of sulphochlorination of n-paraffins C6—C16 (determined by competitive reaction) allow the calculation of sulphochlorination rates of the different C—H-bonds in the n-paraffins C6—C16 relative to one primary C—H-bond in n-octane. For the n-paraffins C6—C8 the relative rates of sulphochlorination of different C—H-bonds agree with the corresponding relative rates of chlorination.
    Notes: Die in Sulfochlorierungsgemischen von n-Paraffinen enthaltenen isomeren Monosulfochloride lassen sich durch Umsetzen mit Dimethylamin/Äther in die gaschromatographisch trennbaren Sulfonsäuredimethylamide überführen. So ist die Isomerenanalyse der Sulfochlorierungsgemische aus den n-Paraffinen C5—C16 möglich. Die Ergebnisse sowie die durch Konkurrenzreaktion ermittelten relativen Sulfochlorierungsgeschwindigkeiten der n-Paraffine C6—C16 gestatten die Berechnung der auf eine primäre C—H-Bindung des n-Octans bezogenen relativen Sulfochlorierungsgeschwindigkeiten der verschiedenen C—H-Bindungen in den Paraffinen C6—C16. Bei den Paraffinen C6—C8 stimmen die relativen Reaktionsgeschwindigkeiten der verschiedenen C—H-Bindungen bei der Sulfochlorierung und bei der Chlorierung innerhalb der Fehlergrenzen überein.
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1038-1042 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemie der Siebenring-Heterocyclen. III. 8-Aryl-6,7,10,11-tetrahydro-benz[b]oxepino-[5,4-d]thiazolo[3,2-a]pyrimidinone-(10)
    Additional Material: 4 Tab.
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  • 157
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1031-1037 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Separation and Identification of the Isomers of Di-1,2-propyleneglycolThe structural isomers of di-1,2-propyleneglycol are separated by means of gaschromatography. The structural and stereoisomeric forms are distinguished and identified by n.m.r. spectroscopy (1H and 13C) and mass-spectrometry.
    Notes: Die vom Dipropylenglykol-(1,2) möglichen strukturisomeren Formen werden gaschromatographisch getrennt. Die Strukturisomere und Diastereomere werden mit Hilfe der 1H-NMR-Signale der Methylgruppen sowie durch 13C-NMR- und Massenspektroskopie unterschieden und zugeordnet.
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1043-1046 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of o-Phenylene Phosphate. XIII. Mass-spectrometric Behaviour of β-Chloroethyl Esters
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1047-1048 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of Halogenated Aldehydes. VII. An Improved Preparation of 1,2,2,2-Tetrachloroethyl Phosphorodichloridate
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976) 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 12-18 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen mit Thiazolo [3,2-b]s-triazol-3(2H)-onen5-Aryl-3-carboxymethylmercapto-1,2,4-triazole 2 werden zu 6-Arylthiazolo[3,2-b]s-triazol-3(2H)-onen 3 cyclisiert. Die Strukturzuordnung wurde anhand von IR- und NMR-Spektren getroffen. 2-Arylmethylen-6-aryl-thiazolo[3,2-b]s-triazol-3(2H)-one 7 wurden nach verschiedenen Methoden erhalten. Die Verbindungen 3 kuppelten mit diazotierten Anilinen zu den 2-Arylhydrazono-6-aryl-3-oxo-2,3-dihydro-thiazolo[3,2-b]s-triazolen 8. Unter der Einwirkung von Aminen auf 3a wird der Thiazolonring unter Bildung der substituierten 5-Phenyltriazolyl-(3)-mercapto-acetamide 9 geöffnet.
    Notes: 5-Aryl-3-carboxymethylthio-1,2,4-triazoles 2 are cyclised to 6-arylthiazolo[3,2-b]-s-triazol-3(2H)-ones 3. This structural assignment has been based on IR and NMR spectra. 2-Arylmethylene-6-arylthiazolo[3,2-b]-s-triazol-3(2H)-ones 7 were prepared by several methods. Compounds 3 coupled with diazotised anilines to give 2,3-dihydro-6-arylthiazolo[3,2-b]-s-triazole-2,3-dione 2-arylhydrazones 8. The action of amines on 3a opens the thiazolone ring with the formation of substituted (5-phenyltriazol-3-ylthio)-acetamides 9.
    Additional Material: 5 Tab.
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  • 162
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Chelates of Unsaturated 1,2-DithioethersThe dialkyl- and diaralkyldithioethers of ethylenebisthiol (edt) and xylenedithiol form cationic 1:2 chelates with the d8-metal ions AgI and CuI, which have been isolated and characterized. PdII- and PtII-halides yield neutral mixed ligand complexes of the type Me (L—L) X2 (L—L = dithioether, X = halogen). The dibenzyldithioether of edt is cleaved oxidatively by CuII and yields dibenzyldisulfide, CuI and an unidentified product.
    Notes: Dialkyl- und Dibenzyldithioäther von Äthylendithiol (edt) und Xyloldithiol (xdt) bilden mit AgI und CuI kationische 1:2-Chelate, welche isoliert und charakterisiert wurden. PdII und PtII ergeben mit diesen Liganden neutrale Chelate des Typs Me(L—L)X2 (L—L = Ligand; X = Halogen). Bei der Umsetzung von Dibenzyldithioäthylen mit CuII findet eine Oxydation des Liganden statt, und man erhält CuI, Dibenzyldisulfid und ein undefiniertes Produkt.
    Additional Material: 4 Tab.
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  • 163
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 26-38 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 2-Phenyl- and 2-Methyl-2,3-dihydro-1,4-dithiin-5,6-dicarboxylic Acid ImideThe hydrolysis of 2-phenyl- and 2-methyl-5,6-dicyano-2,3-dihydro-1,4-dithiine yields the corresponding dicarboxylic acids, diamides and the imides 1, 2. Substitution reactions on the imido group of 1 and 2 give the N-potassium, N-bromo, N-hydroxymethyl, N-methoxymethyl and N-chloromethyl derivatives. The latter reacts with salts of P-esters forming compounds of the general formula: The reaction of primary or secondary amines with 1 and 2 in the presence of formaldehyde leads to as result of an α-aminomethylation. The structure of the prepared compounds is discussed on the basis of their 1H-NMR-, mass- and IR-spectra.
    Notes: Im Verlauf der Hydrolyse von 2-Phenyl- bzw. 2-Methyl-5.6-dicyano-2.3-dihydro-1.4-dithiin lassen sich nicht nur die entsprechenden Dicarbonsäuren und Biscarbonsäureamide, sondern auch die Imide 1 und 2 isolieren. Durch Substitution am Imidstickstoff von 1 und 2 gelangt man zu den N-Kalium-, N-Brom-, N-Hydroxymethyl-, N-Methoxymethyl- und N-Chlormethyl-Derivaten. Letztere reagieren mit Salzen der Dithiophosphor-,-phosphon-, -phosphinsäure-ester bzw. -esteramide oder mit Diphenylchlorphosphin und Schwefel zu Verbindungen der allgemeinen Formel: Primäre und sekundäre Amine setzen sich mit 1 oder 2 in Anwesenheit von Formaldehyd im Sinne einer α-Aminomethylierung zu um. Die Struktur der dargestellten Verbindungen wird anhand von 1H-NMR-, Massen- und IR-Spektren bestätigt.
    Additional Material: 2 Tab.
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  • 164
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 1-11 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Influence of the Solvent on the Acidity of Substituted 2,3-Butanedione OximesThe oximes and dioximes of substituted 2,3-butanediones and their corresponding cations and anions may be classified as neutral, pseudo-neutral, and anion acids. Their electrolytic dissociation may be described by the protonation constants cK1n of their conjugated bases. In dioxane-water mixtures with an increasing content of dioxane a strong increase of cK1n is observed for neutral and anion acids, but only a slight one for the pseudo-neutral acids. The change of cK1n is attributed to the influence of the dielectric constant and to differences in the solvatation of the acids and of their conjugated bases in mixtures with a different content of dioxane.In the case of the 1-amino-2,3-butanedione 2-oximes and of the 1-amino-2,3-butanedione dioximes, two tautomeric species are observed, the ammonium-oximates and the amine-oximes. The shift of the tautomery equilibrium to the amineoxime in solutions with a high content of dioxane causes an abnormal dependence of cK1n on the composition of the solvent.
    Notes: Die Oxime und Dioxime der substituierten Butandione-(2,3) und die von ihnen abgeleiteten Kationen und Anionen lassen sich als Neutral-, Pseudoneutral- und Anionsäuren klassifizieren. Ihre elektrolytische Dissoziation kann durch die Protonierungskonstanten cK1n der konjugierten Basen beschrieben werden. In Dioxan-Wasser-Mischungen steigen mit zunehmendem Dioxan-Gehalt die cK1n-Werte bei den Neutral- und Anionsäuren stark, bei den Pseudoneutralsäuren schwach an. Der Gang wird auf den Einfluß der Dielektrizitätskonstante und auf die Änderung der Solvatation der Säuren und ihrer konjugierten Basen mit der Lösungsmittelzusammensetzung zurückgeführt. Die 1-Amino-butandion-(2,3)-oxime-(2) und die 1-Aminobutandioxime-(2,3) existieren in einer inneren Ammonium-oximat- und in einer Amin-oxim-Form. Die Verschiebung des Tautomeriegleichgewichtes nach der Seite der Amin-oxim-Form mit steigendem Dioxangehalt des Lösungsmittels erklärt den anomalen Gang in den cK1n-Werten dieser Verbindungen.
    Additional Material: 4 Ill.
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  • 165
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 39-50 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 2-Arylamino-3-nitroquinolinesCondensation of 1-nitro-2,2-bis(methylthio)ethylene with esters of anthranilic acid yields 2-arylamino-3-nitro-4-quinolones. 2. Analogously, from 1-nitro-2-anilino-2-methylthioethylene and o-aminoketones, 2-anilino-3-nitroquinolines 4 are obtained which can be reduced to 2-anilino-3-amino-quinolines 7. The latter undergo cyclizations by usual methods to yield substituted triazolo-, imidazolo-, diazepino- and pyrazino-quinolines 9-12. Reaction of ethyl-2-aminothiophene-3-carboxylates with 1-nitro-2-anilino-2-methylthio-ethylene affords 2-anilino-3-nitrothieno[2,3-b]-4-pyridones 5.
    Notes: 1-Nitro-2,2-di-(methylmercapto)-äthylen kondensiert mit Anthranilsäureestern zu den 2-Arylamino-3-nitrochinolonen-(4) 2. Analog reagiert 1-Nitro-2-anilino-2-methylmercaptoäthylen mit o-Amino-ketonen zu 2-Anilino-3-nitrochinolinen 4, deren Reduktion 2-Anilino-3-aminochinoline 7 liefert. Letztere lassen sich nach bekannten Methoden zu substituierten Triazolo- 9, Imidazolo-10, Diazepino-11 und Pyrazino[b]chinolinen 12 cyclisieren. Bei der Reaktion von 2-Amino-thiophen-3-carbonsäureestern mit 1-Nitro-2-anilino-2-methylmercaptoäthylen entstehen 2-Anilino-3-nitro-thieno[2, 3-b]pyridone-(4) 5.
    Additional Material: 6 Tab.
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  • 166
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 79-86 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides of Fluorine Carbohydrates. XV. Synthesis of Thymine Nucleosides of 6-Fluoro-D-glucopyranose and 6-Fluoro-D-galactopyranose1-β-D-glucopyranosyl thymine 1 and 1-β-D-galactopyranosyl thymine 13 react with equimolar amounts of tosyl or mesyl chloride to give predominantly the 6′-O-sulphonyl derivatives 6 and 7 or 14 and 15. Simultaneously small amounts of the 2′,6′-di-O-sulphonyl derivatives 4 and 5 are obtained. The tosyl derivative 6 reacts easily with alkali fluoride to give the 6′-deoxy-6′-fluoro nucleoside 10. In contrast to the glucose series the corresponding conversion of the 6′-sulphonyloxy-galactose derivatives is difficult to achieve.The condensation of 2,3,4-tri-O-acetyl-6-O-tosyl-D-glucopyranosyl bromide 2 or 6-deoxy-6-fluoro-1,2,3,4-tetra-O-acetyl-D-galactopyranose 18 with 2,4-bis-O-trimethylsilyl thymine 3 affords, after deacetylation, 6 and 1-(6′-deoxy-6′-fluoro-β-D-galactopyranosyl)thymine 20, respectively.
    Notes: 1-β-D-Glucopyranosyl-thymin 1 und 1-β-D-Galaktopyranosyl-thymin 13 ergeben mit äquimolaren Tosyl-oder Mesylchlorid bevorzugt die entsprechenden 6′-O-Sulfonyl-Nucleoside 6 und 7 bzw. 14 und 15. In geringer Menge entstehen die 2′,6′-Di-O-sulfonyl-Derivate 4 und 5. Während in der Glucose-Reihe besonders die Tosylverbindung leicht mit Alkalifluorid zum 6′-Desoxy-6′-fluor-Nucleosid 10 reagiert, gelingt die analoge Substitution in der Galaktose-Reihe nur schwer.Die Kondensation 2,3,4-Tri-O-acetyl-6-O-tosyl-D-glucopyranosylbromid 2 bzw. von 1,2,3,4-Tetra-O-acetyl-6-desoxy-6-fluor-D-galaktose 18 mit 2,4-Bis-O-trimethylsilyl-thymin 3 führt zu Nucleosiden, die nach der Entacetylierung mit 6 bzw. 1-(6′-Desoxy-6′-fluor-β-D-galaktopyranosyl)-thymin 20 identisch sind.
    Additional Material: 1 Tab.
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  • 167
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 69-78 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrogen Bonds in Solutions of Ortho Phosphoryl Substituted PhenolsIn contrast to open-chained phosphoryl-enols 1 the ortho-P(O)-substituted phenols 4 may be conveniently obtained by cleavage of phenol alkylethers. Rf-values (TLC) demonstrate that the phenols 4 exhibit P=O ⃛ HO hydrogen bonds in solution if the basizity of the phosphoryl O-atom is sufficient. Electronwithdrawing P-substituents lower the probability of this interaction. δOH and Pka data demonstrate that in dimethylsulfoxide only phosphinoxides 4a-g give P=O ⃛ HO bridges. Arylesters of phosphonic acids 4i-k add DMSO-molecules via S=O … HO hydrogen bonds. This difference is mainly a result of inductive effects. UV-spectra refer to a probably small contribution of P-phenyl substituents to conjugation.
    Notes: ortho-P(O)-substituierte Phenole 4 sind im Gegensatz zu offenkettigen Phosphoryl-enolen 1 durch Spaltung der Phenol-alkyl-äther gut zugänglich und als Studienobjekte für die gegenseitige Beeinflussung der P = O- und der OH-Gruppe in 1.2-Position einer C=C-Doppelbindung geeignet. Rf(DC)-Werte deuten darauf hin, daß die Phenole 4 in Lösung bei ausreichender Basizität des Phosphoryl-O-Atoms Wasserstoffbrückenbindungen P=O ⃛ H-O ausbilden, während stark elektronenziehende P-Substituenten die Beteiligung der P=O-Gruppe unwahrscheinlich machen. δOH- und Pka-Werte zeigen, daß in Dimethylsulfoxid nur im ersten Fall (Phosphinoxide 4a-g) P=O ⃛ HO-Brücken existieren, während bei Phosphonsäure-arylestern 4i-k Addukte mit DMSO-Molekülen gebildet werden. Für diese Differenzierung sind in erster Linie induktive Substituenten-effekte verantwortlich. Die UV-Spektren deuten lediglich einen geringen konjugativen Beitrag von P-Phenylsubstituenten an.
    Additional Material: 5 Tab.
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  • 168
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrochemical Behavior of N-Aryl-Δ2-pyrazolines. VIII. Relationships between the Anodic and Cathodic Behaviour and the Absorption and Fluorescence Properties of N-Aryl-Δ2-pyrazolinesThe anodic and cathodic half-wave potentials in acetonitrile and dimethylformamide (DMF) and the absorption and fluorescence spectra in DMF and cyclohexane of 61 N-aryl-Δ2-pyrazolines have been measured. The following correlation has been found between the difference of the half-wave potentials E1/2OX-E1/2red of the first oxidation and reduction steps and the fluorescence maximum in DMF, h · νmaxf: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm h} \cdot v_{{\rm max}}^{\rm f} = {\rm E}_{{\rm 1/2}}^{{\rm ox}} - {\rm E}_{{\rm 1/2}}^{{\rm red}} - 0,45 \pm 0,04{\rm eV} $$\end{document} This confirms the charge-transfer character of the corresponding spectroscopical transition. The deviations of some compounds from this correlation are due to differences in the electrochemical behaviour as, e.g., the cathodic elimination of halogen from halogen substituted pyrazolines or the intramolecular hydrogen bond in 1, 5-diaryl-3-o-hydroxyphenyl-Δ2-pyrazolines.
    Notes: Die anodischen und kathodischen Halbstufenpotentiale in Acetonitril bzw. Dimethylformamid (DMF) sowie die Absorptions- und Fluoreszenzspektren in DMF und Cyclohexan von 61 N-Aryl-Δ2-pyrazolinen wurden gemessen. Zwischen der Differenz der Halbstufenpotentiale E1/2ox  -  E1/2red der ersten Oxydations- und Reduktionsstufe und dem Fluoreszenzmaximum in DMF h ·maxf besteht folgender Zusammenhang, der den Charge-Transfer-Charakter des entsprechenden spektroskopischen Überganges bestätigt: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm h} \cdot v_{{\rm max}}^{\rm f} = {\rm E}_{{\rm 1/2}}^{{\rm ox}} - {\rm E}_{{\rm 1/2}}^{{\rm red}} - 0,45 \pm 0,04[{\rm eV}] $$\end{document} Die Abweichungen einiger Verbindungen von dieser Beziehung sind auf strukturbedingt veränderte elektrochemische Eigenschaften wie z. B. die kathodische Halogenidabspaltung der halogensubstituierten Pyrazoline oder die Bildung einer intramolekularen Wasserstoffbrücke bei den 1, 5-Diaryl-3-o-hydroxyphenyl-Δ2-pyrazolinen zurückzuführen.
    Additional Material: 4 Ill.
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  • 169
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 87-95 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Functionally Substituted Organotin Compounds. I ω-Triethylstannylalkylphosphonic- and -phosphinic Estersω-Triethylstannylalkylphosphonic- and -phosphinic esters 1 can be synthesized by radical addition of triethylstannane to alkenylphosphonic- and -phosphinic esters. Their reaction with bromine or hydrochloric acid causes a substitution of an ethyl group forming organotin halides 2 and 3. On alkaline hydrolysis of stannylsubstituted phosphinic esters, the acids 4 were obtained which can be transformed into the cyclic organotin phosphinates 5. Lithium aluminium hydride reduces ω-triethylstannylalkylphosphonic- and -phosphinic esters to ω-triethylstannyl-alkylphosphines 6. The P-phenylsubstituted compounds 6 are oxidized by sulfur via the dithioacids 8 to 1-diethyl-3-phenyl-1,2,3-stannathiaphospholane- and -phosphorinane-P-sulfid 9, respectively.
    Notes: Durch radikalische Addition von Triäthylstannan an Alkenylphosphon-und -phosphinsäureester werden ω-Triäthylstannylalkylphosphon- und -phosphinsäureester 1 synthetisiert, die durch Umsetzung mit Brom bzw. Chlorwasserstoff unter Substitution eines Äthylrestes die Organozinnhalogenide 2 und 3 liefern. Aus der alkalischen Hydrolyse der stannyl-substituierten Phosphinsäureester resultieren die Säuren 4, die in die cyclischen Organozinnphosphinate 5 überführbar sind. Lithiumalanat reduziert ω-Triäthylstannylalkylphosphon- und -phosphinsäureester zu ω-Triäthylstannylalkylphosphinen 6, deren P-phenylsubstituierte Vertreter durch Schwefel über die Dithiosäuren 8 zu 1-Diäthyl-3-phenyl-1,2,3-stannathiaphospholan- bzw. -phosphorinan-P-sulfid 9 oxydiert werden.
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  • 170
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 116-126 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Substituted Phosphonates. XIX. Derivatives of Aminomethane-bis-phosphonic AcidAminomethane-bis-phosphonic acid tetraethylesters have been prepared by various methods. Chlorination and hydrolysis of these compounds have been studied in detail.
    Notes: Aminomethan-bis-phosphonsäure-tetraäthylester wurden nach verschiedenen Verfahren synthetisiert. Die Chlorierung und die Hydrolyse dieser Verbindungen wurden eingehend untersucht.
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  • 171
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 105-115 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gibberellins. XXXV. Synthesis of Neutral and Amino-substituted Amides of the Gibberellin A3 and A1 SeriesThe synthesis of neutral and amino-substituted amides of the gibberellin A3 and A1 series via aminolysis of the corresponding gibberellin carboxylic acid anhydrides is described. The mass spectra and 1H-NMR data of these compounds are discussed.
    Notes: Es wird die Synthese einer Anzahl neutraler und basischer Amide der Gibberellin-A3- und -A1-Reihe durch Aminolyse entsprechender Gibberellinanhydride beschrieben. Massen- und 1H-NMR-spektroskopische Befunde an dieser Verbindungsklasse werden mitgeteilt.
    Additional Material: 3 Ill.
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  • 172
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 96-104 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Poly-n-alkyl-methylsiloxanes: Effective Cloud Point and Pour Point Depressants for Petroleum DistillatesLinear poly-n-alkyl-methylsiloxanes of the formulae (CH3)3Si-[OSi(CH3)R]n-OSi(CH3)3 with R = C12H25, C14H29, C16H33 and n ≤ 8 were prepared by various synthetic methods. Both these substances and the analogous cyclic siloxane derivates [OSi(CH3)R]m (m = 3…6) were found to be effective cloud point and pour point depressants for petroleum middle distillates.Some ideas concerning the mechanism of could point depression are discussed.
    Notes: Nach verschiedenen Synthesemethoden wurden lineare Poly-n-alkylmethylsiloxane (CH3)3-[OSi(CH3)R]n-OSi(CH3)3 mit R = C12H25, C14H29, C16H33 und n ≤ 8 hergestellt. Sie erwiesen sich in Erdölmitteldestillaten ebenso wie die analogen cyclischen Siloxanderivate [OSi(CH3)R]m (m = 3…6) als wirksame Stockpunkterniedriger und zeigten darüber hinaus die relativ seltene Fähigkeit der BPA-Punktdepression.Einige Überlegungen zum Wirkungsmechanismus der BPA-Punktdepression werden mitgeteilt.
    Additional Material: 2 Ill.
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  • 173
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 127-143 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Substituted 1,4,2-DithiazinesAzidions react with 1,3-dithiolium salts to give the 2-azido-1,3-dithiolen 2. In solution and at room temperature, 2-azido-2-methylthio-1,3-dithiols of the type 2a eliminate nitrogen forming N-methylthio-2-imino-1,3-dithiols 4 and 3-methylthio-1,4,2-dithiazines 5a, c-1. The thermolysis of the more stable 2-azido-1,3-dithiol 2b proceeds in a less distinct way. Compounds 4, exhibiting the properties of sulfenimides, easily yield the 2-amino-1,3-dithiolium salts 6. The 1,4,2-dithiazines 5 are unstable at higher temperatures. They are converted to isothiazoles 11 with extrusion of sulphur. In a side reaction the compounds 5a, c-k eliminate methyl rhodanide, and 5b eliminates hydrogen cyanide. The formation of a dithiet or a dithioketone as an intermediate is proved by trapping with dimethyl fumarate. With strongly electrophilic reagents compounds 5 undergo ring contraction, yielding 1,3-dithiols, and with strong bases they react with ring opening.
    Notes: Azidionen reagieren mit 1.3-Dithioliumsalzen 1 zu 2-Azido-1.3-dithiolen 2. 2-Azido-2-methylmercapto-1.3-dithiole vom Typ 2a spalten in Lösung bereits bei Raumtemperatur Stickstoff ab, wobei sich neben N-Methylmercapto-2-imino-1.3-dithiols 4 3-Methylmercapto-1.4.2-dithiazine 5a, c-1 bilden. Die Thermolyse des stabileren 2-Azido-1.3-dithiols 2b verläuft weniger übersichtlich. Als Sulfenimide lassen sich die 4 leicht zu 2-Amino-1.3-dithioliumsalzen 6 spalten. Die 1.4.2-Dithiazine 5 sind thermoinstabil. Sie gehen unter Schwefelextrusion in Isothiazole 11 über. Gleichzeitig spaltet sich aus den 5a, c-k Methylrhodanid bzw. aus 5b Blausäure ab. Als Intermediärprodukt wurde ein Dithiet bzw. Dithioketon durch Abfang mit Fumarsäuredimethylester wahrscheinlich gemacht. Mit stark elektrophilen Reagenzien setzen sich die 5 unter Ringverengung zu 1.3-Dithiol-Derivaten und mit starken Basen unter Ringspaltung um.
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 157-160 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Aminoacids and Derivatives. VIII. A Simple Synthesis of PhosphinothricinA simple and economical synthesis of D,L-phosphinothricin 2 - the active part of an antibiotical effective heterotripeptide which was isolated from Streptomyces viridochromogenes - is described.
    Notes: Es wird eine einfache und ökonomische Synthese von D, L-Phosphinothricin 2, dem wirksamen Bestandteil eines aus Streptomyces viridochromogenes isolierten antibiotisch wirksamen Heterotripeptids beschrieben.
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  • 175
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 144-148 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzazoles. XXX. Amidomethylation of Aromatic Compounds with 1,3-Bis-chloromethyl-benzimidazolone and 1,3-Bis-chloromethyl-benzimidazolthioneAromatic hydrocarbons are amidomethylated on treatment with 1,3-bis-chloromethyl-benzimidazolone 3 or 1,3-bis-chloromethyl-benzimidazolthione 4 in the presence of aluminium chloride, to give 1,3-bis-arylmethyl-benzimidazolones 5-6 and 1,3-bis-arylmethyl-benzimidazolthiones 7-9, respectively. The amidomethylation of sodium phenates or potassium phenates with 3 and 4 leads to the 1,3-bis-aryloxymethyl-benzimidazolones 10-12 or to the corresponding benzimidazolthiones 13-16 which may be used for the characterization of phenols.
    Notes: Aromatische Kohlenwasserstoffe lassen sich mit 1.3-Bis-chlormethyl-benzimidazolon 3 und mit 1.3-Bis-chlormethyl-benzimidazolthion 4 bei Gegenwart von Aluminiumchlorid zu 1.3-Bis-arylmethyl-benzimidazolonen 5-6 bzw. zu 1.3-Bis-arylmethyl-benzimidazolthionen 7-9 amidomethylieren. Die Amidomethylierung von Natrium- oder Kalium-phenolaten mit 3 und 4 führt zu den 1.3-Bis-aryloxymethyl-benzimidazolonen 10-12 bzw. zu entsprechenden Benzimidazolthionen 13-16, die zur Charakterisierung der Phenole geeignet sind.
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  • 176
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 149-156 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of N-acylated Thiophosphinic AmidesN-Acyl-, N-thioacyl- and N-sulfonyl-substituted thiophosphinic amides are prepared by the reaction of metallated acid amides with acid chlorides. The compounds exist as imides and form intermolecular hydrogen bonds. Their pKa-values were potentiometrically determined and show a considerable acidifying influence of the thiophosphinic residues. Methylation of the imides with diazomethan gives predominantly S-methylesters of imidothiophosphinic acids.
    Notes: N-Acyl-, N-Thioacyl- und N-Sulfonyl-substituierte Thiophosphinsäureamide werden durch Reaktion metallierter Säureamide mit Säurechloriden erhalten. Die Verbindungen liegen als Imide vor und bilden im festen Zustand intermolekulare Wasserstoffbrücken. Ihre potentiometrisch bestimmten Aciditätskonstanten zeigen einen beträchtlichen acidifizierenden Einfluß der Thiophosphinylreste an. Die Methylierung mit Diazomethan führt hauptsächlich zu S-Methylestern der Imidothiophosphinsäuren.
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  • 177
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 168-172 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
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  • 178
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976) 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 179
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 173-176 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 180
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 161-167 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 2,1-Benzisothiazolin-3-onesDependent on the substituent group at the nitrogen the sodium salts of thioanthranilic acids 3, availabel from isatoic anhydrides 1 and sodium hydrogen sulphide, yield on oxidation 2,1-benzisothiazolin-3-ones 4 or bis-anthranoyl disulphides 5. The latter are cyclized under special conditions to yield 4. From 4 and oxalyl chloride, 3-chloro-2,1-benzisothiazolium chlorides 7 are available which give with hydrogen sulphide the thiones 6 and with dimethyl aniline the polymethines 9. The dyestuffs 9 can also be prepared from the 3-methylthio-2,1-benzisothiazolium salts 8, obtainable by alkylation of compounds 6.
    Notes: Die aus Isatosäureanhydriden 1 und Natriumhydrogensulfid erhältlichen Natriumsalze der Thioanthranilsäure 3 liefern bei der Oxydation in Abhängigkeit vom Substituenten am Stickstoff 2.1-Benzisothiazisothiazolinone-(3) 4 oder Dianthranoyl-disulfide 5. Die 5 können unter speziellen Bedingungen zu 4 cyclisiert werden. Aus 4 sind mit Oxalychlorid 3-Chlor-2.1-benzisothiazoliumchloride 7 zugänglich, die mit Schwefelwasserstoff zu den Thionen 6 und mit Dimethyl-anilin zu den Polymethinen 9 reagieren. Die Farbstoffe 9 können auch aus den durch Alkylierung der 6 zugänglichen 3-Methylmercapto-2.1-benzisothiazoliumsalzen 8 dargestellt werden.
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  • 181
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 177-184 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Elucidation of the Molecular Structure of Petroleum Constituents by NMR Spectroscopy. I. Structure of Branched Paraffins in Petroleum CrudeA correlation between the 13C resonance peaks and possible structural elements of branched paraffins of petroleum fractions is given. New information concerning the structure of branched paraffins of petroleum crude is provided.
    Notes: Es wird eine Zuordnung der 13C-Resonanzen der Paraffine der Roherdölfraktionen zu entsprechenden C-Atomen möglicher Strukturelemente vorgenommen. Daraus ergeben sich neue Informationen über die Struktur der Isoparaffine des Erdöls.
    Additional Material: 1 Ill.
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  • 182
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 193-201 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 1, 3-Azarsolidine-2-thionesSecondary 2-aminoethylarsines of the type RAs(H)—CH2CH2—NHR′ react with CS2 yielding 1,3-azarsolidine-2-thiones. Under suitable conditions the corresponding ammonium salts of the 2-arsinoethyl-dithiocarbamates are isolable as primary reaction products. 1,3-Azarsolidine-2-thiones are attacked by electrophilic agents on the sulfur atom yielding 2-alkylthio- and 2-organostannylthio-azarsolines, respectively, as well as 1,3-azarsolidine-2-ones.
    Notes: Sekundäre 2-Amino-äthylarsine, RAs(H)—CH2—CH2—NMR′, reagieren mit CS2 zu den 1.3-Azarsolidin-thionen. Unter geeigneten Bedingungen sind dabei auch die Ammoniumsalze der 2-Arsinoäthyl-dithiocarbamate als primäre Reaktionsprodukte isolierbar. Die 1.3-Azarsolidin-2-thione reagieren mit elektrophilen Agentien am Schwefelatom, wobei 2-Alkylthio- bzw. 2-Organostannylthioazarsoline sowie 1.3.-Azarsolidin-2-one zugänglich sind.
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  • 183
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 185-192 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Heterocycles by C—C-Bond Formation. I. Noble Metal Catalyzed Cyclization of Acrylic Acid Diallyl AmideThe action of PdCl2 on acrylic acid diallyl amide 1 leads, by ring closure between the acryloyl group and one of the allyl groups, to a mixture of the five-membered heterocycles 2, 3, 4, 5 and 6. Additionally, some 7 and 8 is formed by ring closure involving both allyl groups. The latter reaction is predominant on catalysis by RhCl3, resulting in the formation of 7 besides some 2, 4 and an isomer 14. With more RhCl3, quantitative elimination of allyl groups from N-allyl acid amides is observed.
    Notes: Einwirkung von Palladiumchlorid auf Acrylsäure-diallylamid 1 führt zu einem Gemisch von fünfgliedrigen Heterocyclen, wobei überwiegend Ringschluß zwischen der Acryloylgruppe und einer Allylgruppe erfolgt (Bildung von 2, 3, 4, 5 und 6), daneben Ringschluß zwischen den beiden Allylgruppen zu 7 und 8. Der letztere Fall überwiegt bei Rhodiumkatalyse (Bildung von 7); daneben entstehen geringe Mengen 4, 2 sowie ein weiteres Isomeres 14. Bei Anwendung größerer Rhodiummengen lassen sich N-ständige Allylgruppen von Säureamiden quantitativ abspalten.
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  • 184
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 207-220 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions towards the Reaction Behaviour of Dialkyl Oxo-alkane-phosphonatesDialkyl oxo-alkane-phosphonates react with dioles and their thio-analogues forming ketales and thioketales 1-19 of the general formulaThe arylhydrazones prepared from substituted diethyl oxo-alkane-phosphonates and aromatic diazonium salts can be cyclized without preliminar isolation to give the diethyl indolyl-2-phosphonates 20. 1-Arylidene-2-oxo-propane phosphonic acid esters 22 and 23 react with ethyl β-aminocrotonate through MICHAEL addition followed by enamine formation to yield alkyl dihydropyridine-3-phosphonates 24 and 25. I. R. data of the compounds prepared are recorded.
    Notes: Oxo-alkan-phosphonsäuredialkylester reagieren mit Diolen bzw. entsprechenden Schwefelanaloga zu Ketalen bzw. Thioketalen 1-19 der allgemeinen Formel Die aus verschieden substituierten Oxo-alkan-phosphonsäurediäthylestern 21 und aromatischen Diazoniumsalzen zugänglichen Arylhydrazone lassen sich ohne vorherige Isolierung zu den Indolyl-2-phosphonsäurediäthylestern 20 cyclisieren. Die 1-Aryliden-2-oxo-propan-phosphonsäureester 22 und 23 liefern mit β-Aminocrotonsäureäthylester im Sinne einer MICHAEL-Addition und anschließender Enaminbildung die Dihydropyridin-3-phosphonsäureester 24 und 25.Die IR-Daten der dargestellten Verbindungen werden mitgeteilt.
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  • 185
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 221-228 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 3-Amino-1,2-dithiolium Salts and their Conversion to 2-Nitro-3-aminothiophenes3-Amino-1.2-dithiolium salts 2a-1 are easily available from 3-chloro-1,2-dithiolium salts 1 and secondary amines.A new procedure to prepare 2-nitro-3-aminothiophenes 3 starting from N,N-substituted 3-amino-5-phenyl-1,2-dithiolium salts 2 is described which consists in a nucleophilic exchange of a sulfur atom for the carbon atom of nitromethane.The structure of 3 has been confirmed by reductive cyclization and by spectroscopic methods.
    Notes: 3-Amino-1.2-dithioliumsalze 2a-1 sind in einfacher Weise aus 3-Chlor-1.2-dithioliumsalzen 1 und sekundären Aminen zugänglich.Es wird ein neues Verfahren zur Herstellung von 2-Nitro-3-amino-thiophenen 3 aus N,N-disubstituierten 3-Amino-5-phenyl-1.2-dithioliumsalzen 2 durch nucleophilen Austausch eines Schwefelatoms gegen das C-Atom des Nitromethans beschrieben. Die Struktur der Thiophene 3 wird durch reduktive Cyclisierung und spektroskopische Methoden gesichert.
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  • 186
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 359-368 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 4-Arylazo-isoxazolium Salts4-Arylazo-isoxazolium salts (3, 4), a new class of cationic dyes, are now available by alkylating the isoxazoles 5 and by reacting 1,3-dicarbonyl compounds of the type 1 with N-alkyl-hydroxylamines, respectively.In contrast to the isothiazole system the alkylation of isoxazoles 5 at the ring nitrogen atom does not cause a significant bathochromic shift.4-Arylazo-5-methoxy-isoxazolium salts (8) can be prepared by alkylating 4-arylazo-isoxazolin-5-ones (6 or 11) with dimethyl sulfate.The analogous reaction with 4-arylazo-5-alkylthio-isoxazolines (12, 13) failed, however, the expected 4-arylazo-5-alkylthio-isoxazolium salts (e. g. 14) can be obtained from 12 and trialkyloxonium fluoborate.
    Notes: Es werden Synthesewege für die bisher unbekannten 4-Arylazo-isoxazoliumsalze (z. B. 3, 4, 8, 14), einer neuen Klasse kationischer Farbstoffe, angegeben. 3 bzw. 4 sind durch Alkylierung der Isoxazole 5 bzw. durch Umsetzung von 1,3-Dicarbonylverbindungen des Typs 1 mit N-Alkylhydroxylaminen zugänglich. Im Gegensatz zum Isothiazolsystem kommt es bei den Isoxazolen 5 nach Alkylierung des Ringstickstoffes kaum zu einer Farbvertiefung.4-Arylazo-5-methoxy-isoxazoliumsalze (z. B. 8) sind durch Alkylierung der 4-Arylazo-isoxazolinone-(5) (6 bzw. 11) mit Dimethylsulfat darstellbar. Eine analoge Reaktion mit den 4-Arylazo-5-alkylmercapto-isoxazolen (z. B. 12, 13) gelingt nicht; die erwarteten 4-Arylazo-5-alkylmercapto-isoxazoliumsalze (z. B. 14) sind jedoch aus 12 und Triäthyloxoniumfluoborat synthetisierbar. Für 12, 13 und die 4-Arylazo-isoxazolinthione-(5) (9, 10) werden einfache präparative Vorschriften angegeben.
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  • 187
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 390-398 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organometallic Peroxides. VII. Mechanism of the Decomposition of Bis-organoantimonyl Peroxides. Part IThe decomposition of bis-organoantimonyl peroxides 1 a, b was studied regarding decomposition products, kinetics and the influence of varying conditions.We found that besides heterolytic O-O-cleavage with 1,2-rearrangement, the bromo-substituted peroxide 1 a easily splits off singlet oxygen during decomposition. The mechanism of this reaction has been elucidated.
    Notes: Der Zerfall der Bis-(halogen-triphenyl-antimonyl)-peroxide 1 a und b wurde hinsichtlich der Zersetzungsprodukte, der Kinetik und des Einflusses verschiedener Faktoren untersucht. Es wurde gefunden, daß bei der Zersetzung neben einer heterolytischen Spaltung der O-O-Bindung unter 1.2-Umlagerung bei dem bromhaltigen Peroxid 1 a leicht eine Abspaltung von Singulett-Sauerstoff erfolgt. Der Mechanismus dieser Reaktion wurde aufgeklärt.
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  • 188
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 399-402 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Selektive Komplexbildung zwischen Eu (DPM)3 und dem (Z)-Isomeren von N-[Alkyliden-(2)]-anilinenBei Einwirkung von paramagnetischen Verschiebungsreagenzien wie Eu(DPM)3 auf ein Gleichgewichtsgemisch von (E)- und (Z)-N-[Alkyliden-(2)]-anilinen in CCl4 wurde eine selektive Komplexbildung mit dem (Z)-Isomeren des Ketimins beobachtet.
    Notes: Treatment of an equilibrium mixture of E- and Z-N-(2-alkylidene)anilines in CCl4 with paramagnetic shift reagents such as Eu(DPM)3 displayed a selective complexation with the Z-isomer of the ketimine.
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  • 189
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 409-412 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organo-arsenic Compounds. XXVI. Synthesis of 1.3-Azarsolines2-Aminoalkylarsines of the type RAs(H)CH2CH2NH2 react with formic acid or carbonic acid chlorides to give the corresponding amides 1-3, whereas reaction with iminoester hydrochlorides yields 1,3-azarsolines 4-6. I. R.- and n.m.r.-data are reported.
    Notes: Während bei der Umsetzung von 2-Aminoalkylarsinen des Typs RAs(H)-CH2CH2NH2 mit Ameisensäure oder Carbonsäurechloriden die entsprechenden Amide entstehen, sind durch Reaktion mit Iminoesterhydrochloriden 1.3-Azarsoline erhältlich. IR- und NMR-Daten werden angegeben.
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  • 190
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 403-408 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Substituted Phosphonates. XXI. On the Formation of Hydroxyaryl-substituted Methane-bis-phosphonic Acid Tetraestersα-Amino-α-(4-hydroxy-3,5-di-tert.-butyl-phenyl)-methanephosphonic acid diethylester 1 can be converted by different methods to (4-hydroxy-3,5-di-tert.-butyl-phenyl)-bis-phosphonic acid tetraethylesters 2. Course and intermediates of these smoothly proceeding reactions are investigated.
    Notes: α-Amino-α-(4-hydroxy-3,5-di-tert.-butyl-phenyl) - methanphosphonsäurediäthylester 1 lassen sich auf verschiedenen Wegen in (4-Hydroxy- 3,5-di-tert.-butyl-phenyl)-methan-bisphosphonsäuretetraäthylester 2 überführen. Ablauf und Intermediärprodukte dieser z. T. auffallend glatt verlaufenden Reaktion werden untersucht.
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 420-428 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Peptides. XXIV. Synthesis of [8-α-Amino-γ-phenylbutyric acid]-bradykinin in Combination with Nor- and Homoarginine in Position 9The syntheses of three bradykinin analogues are described with exchange by α-amino-γ-phenylbutyric acid of phenylalanine in position 8. Moreover, arginine in position 9 was replaced by nor- or homoarginine, respectively.
    Notes: Es wird die Synthese von drei Analoga des Bradykinins beschrieben, in denen das Phenylalanin in Position 8 durch L-α-Amino-γ-phenylbuttersäure ersetzt ist. Zusätzlich wurde in Position 9 Arginin gegen Norarginin und Homoarginin ausgetauscht.
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  • 192
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 429-440 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Peptides. XXV. Synthesis of Bradykinin Analogues and Partial Sequences with Tyrosine for Electron Spin Resonance and Fluorescence StudiesThe syntheses of [5-tyrosine, 6-glycine]-, [8-tyrosine, 6-glycine]-, [5,8-Di-tyrosine, 6-glycine]-bradykinin, and the C-terminal partial sequences are described. The analogues have been labelled with the dansyl group or an aminoxyl radical, respectively.
    Notes: Es wird die Synthese von [5-Tyr, 6-Gly]-, [8-Tyr, 6-Gly]-, [5.8-Di-Tyr, 6-Gly]-Bradykinin und der C-terminalen Partialsequenzen beschrieben. Die Bradykininanaloga werden mit dem Dansylrest und einem Iminoxylradikal-Spinmarker substituiert.
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  • 193
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 441-449 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Peptides. XXVI. Synthesis of [8-Phenylglycine]-Bradykinin in Combination with Nor- and Homoarginine in Position 9The syntheses of three analogues of the nonapeptide bradykinin are described with a replacement by C-phenylglycine in position 8. Furthermore, arginine in position 9 has been exchanged by nor- or homoarginine, respectively.
    Notes: Es wird die Synthese von drei Analoga des Nonapeptids Bradykinin mit C-Phenylglycin anstelle von Phenylalanin in Position 8 beschrieben. Zusätzlich wurde Arginin in Position 9 gegen Norarginin oder Homoarginin ausgetauscht.
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  • 194
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    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 413-419 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Optically Active O-Silyl-β-dicarbonyl Compounds. IV. Transsilylation ReactionsThe relationship between the structure of O-silyl-β-dicarbonyl compounds and their tendency to transsilylation reactions is studied by gas chromatography.It is shown that the silyl derivatives of β-diketones and β-dicarboxylic acid diesters easily undergo intermolecular mutual transsilylation reactions. The same compounds quickly transfer silyl groups to free β-dicarbonyl compounds. On the contrary, with silyl derivatives of β-keto esters, o-acylphenols and salicylic acid esters no transsilylation reaction could be observed, and the transfer of silyl groups from O-silyl-β-keto esters to free β-keto esters is only very slow.The ease of transsilylation reactions of O-silyl-β-dicarbonyl compounds correlates with the velocity of racemization of optically active O-silyl-β-dicarbonyl compounds of the same structure. Therefore, we assume that intermolecular transsilylation reactions with inversion of configuration are the main reason for the racemization of optically active O-silyl-β-dicarbonyl compounds.However, no connection could be found between the tendency to transsilylation reactions and the stereochemistry of the reactions of optically active O-silyl-β-dicarbonyl compounds with LiAlH4 which is also dependent on the structure of these compounds.
    Notes: Mit Hilfe gaschromatographischer Studien wird der Zusammenhang zwischen der Struktur von O-Silyl-β-dicarbonylverbindungen und ihrer Neigung zu Transsilylierungsreaktionen untersucht. Es wird gefunden, daß die Silyderivate von β-Diketonen und β-Dicarbonsäureestern Silylreste rasch untereinander austauschen und auf freie 1.3-Dicarbonylverbindungen übertragen, daß dagegen bei Silylderivaten von β-Ketosäureestern, o-Acylphenolen und Salicylsäureestern keine Transsilylierungen zu beobachten sind und Silygruppen-Übertragungen von O-Silyl-β-ketosäureestern auf freie β-Ketosäureester nur langsam ablaufen.Da die Neigung der O-Silyl-β-dicarbonylverbindungen zu Transsilylierungen in allen Fällen mit der Racemisierungsgeschwindigkeit optisch aktiver O-Silyl-Derivate strukturell gleicher β-Dicarbonylverbindungen korreliert, wird angenommen, daß intermolekular unter Umkehr der Konfiguration ablaufende Transsilylierungen die Ursache für die Racemisierung sind.Zusammenhänge zwischen der Neigung zu Transsilylierungen und dem ebenfalls strukturabhängigen sterischen Verlauf der Umsetzungen optisch aktiver O-Silyl-β-dicarbonylverbindungen mit LiAlH4 konnten dagegen nicht aufgefunden werden.
    Additional Material: 1 Ill.
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  • 195
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 450-458 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Birefringence of Cholesteric Liquid Crystals: Cholesteryl n-Alkyl Carbonates and Cholesteryl ChlorideThe principal refractive indices of the cholesteric modification have been studied as a function of temperature and at different wavelengths for 8 homologous cholesteryl-n-alkyl carbonates and for cholesteryl chloride. The measurements were carried out on homogeneously oriented layers using the principle of ABBE's double prism. From the refractive indices of the cholesteric structure the principal refractive indices of the correspondent nematic structure may be calculated.
    Notes: Für 8 homologe Cholesteryl-n-alkylcarbonate sowie das Cholesterylchlorid wurden die Hauptbrechungsindizes der cholesterinischen kristallin-flüssigen Modifikation in Abhängigkeit von der Temperatur und für verschiedene Wellenlängen gemessen. Die Messungen wurden an homogen orientierten Schichten nach dem Prinzip des ABBEschen Doppelprismas durchgeführt. Aus den Brechungsindizes der cholesterinischen Struktur können näherungsweise die Hauptbrechungsindizes der entsprechenden unverdrillten nematischen Struktur berechnet werden.
    Additional Material: 3 Ill.
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  • 196
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 459-462 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyhalogenierung von stickstoffhaltigen Heterocyclen. II Polychlor-1,10-phenanthroline1.10-Phenanthrolin läßt sich mit einer Mischung von Sulfurylchlorid und Thionylchlorid direkt zu einem chromatographisch trennbaren Gemisch von polychlorierten Verbindungen chlorieren.
    Notes: 1,10-Phenanthroline can be chlorinated directly with sulfuryl and thionyl chloride giving a chromatographically separable mixture of polychloro compounds.
    Additional Material: 1 Tab.
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  • 197
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 463-470 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal and Molecular Structure of Peganine. Estimation of its Absolute ConfigurationThe crystal and molecular structure of (-)-peganine hydrochloride 2 have been determined by X-ray structure analysis. Furthermore the absolute configuration of this alkaloid was deduced with the aid of the anomalous scattering at the Cl-atoms. The pyrrolidine ring of 2 has envelope conformation. 2 possesses R-configuration.
    Notes: Mittels Röntgenkristallstrukturanalyse wurde die Molekül- und Kristall-struktur sowie unter Ausnutzung der anomalen Streuung an den Chloratomen des Hydrochlorids von 2 die Absolutkonfiguration von (-)-Peganin 2 bestimmt. Danach besitzt 2 R-Konfiguration.
    Additional Material: 2 Ill.
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  • 198
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 471-478 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Heterocycles by C—C-Bond Formation. II. Catalytic Cyclization of N-Alkyl-N-allyl-acrylamides and N,N-Diallyl Carbonic Acid AmidesN-Alkyl-N-allyl-acrylamides 2 cyclize in the presence of PdCl2 to 1-alkyl-3,4-dimethyl-3-pyrrolin-2-ones 4 and 1-alkyl-4-methyl-3-methylene-pyrrolidin-2-ones 5. Compounds 4 predominate in the mixture. With RhCl3, ring closure gives comparable amounts of lactams 4 and 7 (1-alkyl-3,4-dimethyl-3-pyrrolin-2-ones) besides some product of allyl elimination. N. N-Diallyl carboxylic amides 3 form cyclic enamides (1-acyl-3,4-dimethyl-2-pyrrolines, 9) on the action of PdCl2 besides the products 10 of allyl elimination. RhCl3 effects cyclization of 3 to form 1-acyl-3-methyl-4-methylene-pyrrolidines 11 besides some 9. The acid amide groups of compounds 9 and 11 are shown by n.m.r. spectroscopy to exist as rotamers.
    Notes: N-Alkyl-N-allyl-acrylamide 2 cyclisieren in Gegenwart von Palladiumchlorid zu 1-Alkyl-3.4-dimethyl-Δ3-pyrrolinonen-(2) 4 und 1-Alkyl-4-methyl-3-methylen-pyrrolidinonen-(2) 5, wobei der Typ 4 stark überwiegt. Durch Rhodiumchlorid erfolgt Ringschluß zu vergleichbaren Mengen an Lactamen 4 und 7 (1-Alkyl-3-methyl-4-methylen-pyrrolidinone-(2)); daneben wird Abspaltung des Allylrestes beobachtet. N. N-Diallyl-carbonsäureamide 3 geben mit Palladiumchlorid cyclische Enamide (1-Acyl-3.4-dimethyl-Δ2-pyrroline, 9) neben Produkten der Entallylierung. Rhodiumchlorid bewirkt Cyclisierung von 3 zu 1-Acyl-3-methyl-4-methylen-pyrrolidinen 11 neben wenig 9. In den Verbindungen 9 und 11 wird NMR-spektroskopisch das Vorliegen von rotationsisomeren Säureamidgruppierungen nachgewiesen.
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  • 199
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 489-496 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of α-Phosphinyl-substituted Stilbenes and Related CompoundsDiphenyl-(α-diphenylphosphinyl-phenylmethane)-phosphonate 1d regiospecifically reacts to α-phosphinyl-stilbene or to analogous compounds 2 with aromatic aldehydes under elimination of the phosphoryl group, with very different yields. Cis-trans-mixtures of various composition are formed in dependence on the size of the R4-moiety. The trans-product is preferred if R4 is a small substituent for instance phenyl or pyridyl, but with a large moiety for instance quinolyl, the cis-isomer becomes predominant. The relation between cis- or trans-configuration of the reaction products is determined by the different extent of steric hindrance in the cyclic intermediate states. The analogous reaction with 1b and benzaldehyde does not yield P-substituted stilbene but 1,2-bis-(diphenylphosphinyl)-1,2-diphenylethane 3. The mechanism of this reaction is discussed.
    Notes: α-Diphenylphosphinyl-phenylmethan-phosphonsäurediphenylester 1d reagiert mit aromatischen Aldehyden regiospezifisch unter Abspaltung der Phosphorylgruppe mit stark unterschiedlichen Ausbeuten zu α-Phosphinyl-stilben bzw. analogen Verbindungen 2. Dabei fallen in Abhängigkeit von der Größe des Restes R4 cis-trans-Gemische unterschiedlicher Zusammensetzung an. Bei kleinem Rest, wie z. B. Phenyl oder Pyridyl, entsteht fast ausschließlich das trans-Isomere, bei großem Rest, z.B. Chinolyl, steigt der cis-Anteil, bzw. das cis-Isomere wird zum Hauptprodukt. Die Selektion zwischen cis- oder trans-Konfiguration der Reaktionsprodukte wird bestimmt durch das unterschiedliche Ausmaß der sterischen Hinderung in den cyclischen Übergangszuständen. Die gleiche Reaktion mit 1b und Benzaldehyd ergibt kein P-substituiertes Stilben, sondern 1,2-Bis-(diphenylphosphinyl)-1,2-diphenyl-äthan 3, dessen Bildungsmechanismus diskutiert wird.
    Additional Material: 2 Tab.
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  • 200
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: MO Calculations on the Photographic Development. IX. Experimental and Quantum Chemical Investigations on the Acidity of 5-PyrazolonesThe pKs values of 49 derivatives of 5-pyrazolone are measured by potentiometric titration and their 1H-NMR-spectra recorded in DMSO-d6. The experimental acidity order correlates for structural similar compounds as well with substituent constants and HMO electron densities.
    Notes: Die pKs-Werte von 49 Pyrazolon-(5)-Derivaten wurden durch potentiometrische Titration bestimmt und die 1H-NMR-Spektren der Substanzen in DMSO-d6 aufgenommen. Die experimentelle Aciditätssequenz befindet sich für strukturell ähnliche Verbindungen sowohl mit den Hammett-Konstanten als auch den HMO-Elektronendichten am Reaktionszentrum in guter Übereinstimmung.
    Additional Material: 4 Ill.
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